No evidence of association between subclinical thyroid disorders and common carotid intima medial thickness or atherosclerotic plaque

Background and aims: Increased carotid artery intima-media thickness (IMT) and the presence of plaques have been shown to be predictors of cardiovascular disease. The cardiovascular risk in patients with overt thyroid diseases is related to increased risk of atherosclerosis, but there has been no clear evidence about subclinical disorders. We have assessed whether subclinical thyroid dysfunction is associated with arterial thickening and plaque. Methods and results: The SardiNIA study is a population-based survey on the Italian island of Sardinia. We reviewed data from 5815 subjects (aged 14-102 years), none of whom had overt hyperthyroidism or hypothyroidism or was taking thyroid medication. Serum thyrotropin (TSH), free thyroxine, together with carotid ultrasound IMT and the presence of common carotid plaques were analysed in all subjects. Possible association of IMT and carotid plaques with thyroid parameters was evaluated by univariate and multivariate analyses. IMT was significantly associated with age, sex, smoking, low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol, pulse pressure (PP), history of arterial hypertension, diabetes, and previous cardiovascular events (p = 0.001 or lower, R² = 0.47). Carotid plaques were predicted by age, sex, LDL, PP, history of diabetes, previous cardiovascular events, and the use of statins (p = 0.029 or lower). Thyroid hormone was not predictive of carotid atherosclerosis when adjusted for confounders. Conclusion: Thyroid hormone is not associated with increased IMT or with the presence of carotid artery plaque. Our data do not support the idea that treating subclinical disorders might help to prevent arterial remodelling or carotid atherosclerosis.